Cast drill bit with split-tang element



Jan. 17, 1928.

G. D. SHIELDS CAST DRILL BIT WITH SPLIT TANG ELEMENT W w w e 1 w m Myif, m. m 2 m W M 4 W a u H W W m ,w, m w \fl- J /fi M ma iw 0v F m a m,4,

Jan. 17, 1928. 1,656,296

, G. D. SHIELDS CAST DRILL BIT WITH SPLIT TANG ELEMENT Fil 1 1927, 2Sheets-Sheet 2 I hi QYTOQNEY Patented Jan. 17, 1928.

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CAST DRILL BIT WITH SPLIT-TANG ELEMENT.

Application filed April 2,

As a, be inferred from the above title,

' it is an object of this invention to provide means for securing a hardblade or blades, such as may be formed by castmgor by the u subdivisionor grinding of a flat stock, for rotation by a drill string, or the hke;and in preference to welding a threaded tang element onto a suitableblade or body, or providing a one-piece tang element with means for itsreliable retention upon a shank integral with a drill blade or body, Ihere n propose to employ a two-plece or otherspllt tangelement,--relying elther upon means such as a removable collar or uponan 1nli teri'orly threaded element, such as a tangreceiving box, or uponboth to holdthe mentioned parts in their assembled relat1on-.

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(gther objects of my invention, in which I so may employ either suitablyground sect ons of flat stock (in the case of fish-tall blts) orone-piece castings, from a hard metal as a manganese steel, or the l1ke,and which (always providing a shank integrally or otherwise rigidlyconnected with blade sections) '1 provide for a downward ire-elation oflubricating liquid either enternally of said shank therethrough, may beleast appreciated. the following do, so scri'otion of illustrativeembodiments of my invention taken in connection with the ap= pendedclaims and accompanying drawings,

which a 1 may be referred to-as an elevational view, showing anembodimentof my 1nvention comprising a blade of fish-tail type,--- suchas may be formed by casting or by suitably grinding a section of flatstock, too hard for convenient machining, to provide a shank integralwith a blade.

Fig. 2 is a vertical sectional view taken substantially as indicated bythe line 2-2 of Fig. 1, but showing also the lower end of a box orinteriorly threaded retaining elemerit hereinafter referred to asserving both tor a securing and a rotating effect.

Fig. 3 is a horizontal sectional view, taken substantially as indicatedby the line 3-3 of Fig. 1. 1

l Fig. 4 is a sectional view, comparable with Fig. 3 but showing afeature of modlfication hereinafter referred to.

Fig. 5 is an elevational view comparablewith Fig. 1, but showing analternative 1927. Serial No. 1230,429.

form embodyin a star blade cast integral with a hollow s ank.

Fig. 6 is a horizontal section, taken substantially as indicated by theline 6-6 of "star blade,-parts being broken away.

perspective view showing one' Fig. 8 is a completesection of a two-piecetang element, adapted to cooperate with a like tan element in thesecuring of a cast or other 'lade having a suitable shank, at the lowerend oi a dril string (or to any suitable rotary element) provided with abox or female retaining element adapted to hold said tank sections inassembled relationship.

Referring first to the details of that specific embodiment of myinventionillustrated in Figs. 1, 2 and 3, I show a fish-tail blade 11,such as may be formed by suitably grinding a section of flat bar stock,as having an enlargement 13, at or near its upper end,-the enlargementreferred to being provided with beveled surfaces 14, 14, which have aninward inclination same effectively to contact with correspondin lyinclined surfaces, 15 (shcwnaae coni cal) provided in the upper ends oftang sections .16, 16.

Thetang'sections 16, 16 are shown as integral with body sections 17,17'" and as provided not only with pin threads 18 uponsemi-frusto-conical positions thereof but with additional threads 19, ina central region, intermediate between said frusto conical, portions andsaid body portions, said central region being adapted to carry a lockingband or ring 20.

In case the locking element is retained, as above implied, by a.threaded engagement, I consider it best not only to adapt the same toengage threads distinct from those provided upon the pin tive tangsections but also to employ lefthand threads at 19; but it should beunder-' stood that, dqoending upon the materials and the use intended,the lockin element 20 may ,either be secured in an a ternative manner orentirely omitted,-rcliance being then placed upon engagement between thetwo-part tang element and any box, or the like, in which the same mayberecelved, t0

adapting the portions of the respec-.

retain the mentioned parts in their assembled relation'ship,the bodysections 17, 17 beingshown as respectively provided with deep notches21, 21, suitably shaped to interfit with and to impart rotation to thering 2O being optionally provided thereon and the shank 12" being shownas entirely rectangular. The shanks 12 and 12 are shown as adaptedclosely to interfit within verticalgrooves 25, provided in the sections16, 16 or in corresponding grooves 25", 25", provided in the tangsections 16, 16*; but may provide in 16, 16 or in 16, 16" additionalvertical channels such as are indicated at 24, 24in 'Figs. 1 to 3inclusive; or, as indicated in the figures last referred to I may rely,for circulation purposes, partially upon channels 23, 23, out rom thetang sections 16, 16 and partially upon supplemental channels 24, 24 outin the shank 12 and/or the blade 11.

Consistently with the foregoing, I show in Figs. 5-8 an alternative formin which a star blade comprising sections 11" integral with a hollowshank 12" (upwardly-terminating in an enlargement 13") is provided witha 2-part tang element comprising sections 16" and 16",no locking rinbeing employed therewith. In this emb iment of my invention, dispensingwith all effort to provide a wedge-fit between correspondingly inclinedsurfaces (such as the mentioned surfaces 14, 14, and 15, 15), I employsubstantially flat shoulders 14", 14" in engagement with oppositely. disosed surfaces 15' 15", to prevent longitu inal movement of the tangsections 16", 16" relatively to the shank 12"; and I show the shank 12"as not only cylindrical in form to. adapt the same for engagement bycorrespondingly curved surfaces 25", within the res ctive tang sections,but as provided wit a longitudinal passage 23", downwardly terminatingin'separate openings, 24", for the delivery of a lubricating li uid;and, in this form of my lnvention, eac of the mentioned tang sectionsmay be provided with a body portion 17", 17", having not only anintermediate notch or notches 21" but also two halfnotches 21",matinghalf-notches bein adapted to cooperate in the engagement 0 alternateblade sections comprisin shoul ders 22", disposed therebetween; and thedescribed parts may be held in their assembled relatioriship, pendingthe insertion of the describedsectional pin within a suitable boxprovided on a rotatable element, by'means such as a mere wire 20",.shownas disposed in an out-of-the-way position below the threads 18", 18".

In all forms of my present invention, it will be seen that therespective tang sections 16, 16 (or 16", 16", 16", 16") are providedwith oppositely disposed, fiat longitudinal faces 26, (26, 26") inradial planes; and whether or not annular means (such as thelocking-element 20 or a drive collar 20 or the mere wire 20") areemployed, reliance may be entirely or largely placed upon the clampingeffect of a suitable interiorly threaded box 27, or its equivalent (seeFig. 2 only) to hold the mentioned tang sections together, and rigidlyto retain b ade sections therebetween, during the rotation of the entireorganization, for a drilling efiect.

Although I have described by present invention with particular referencetoa well drilling bit,'it Will be understood that the principles thereofare believed to be of somewhat general application to all kinds oftools, as providing means for the securing of cast blades, too hard tobe conveniently machined, with a machined tang, suitable for use inimparting rotation thereto; and it should be understood also thatvarious features of my invention might be independently emplo ed, andthat numerous modifications additional to those herein suggested mighteasily be devised by workers skilled in the arts to which this caserelates, without the slightest departure from the spirit and scope of myinvention, as the same is indicated above and in the following claims.

I claim as my invention:

1. In a drill bit: a blade formed of material too hard for convenientmachining and "provided with a shank which has a terminal enlargement;and a sectional tang element provided with meansfor causing said bladeto rotate therewith.

2. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided with threads and with means forsecuring said blade to-rotate,-said lastmentioned means com, risingnotched body portions integral wit sections of said tang.

3. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided with threads and with means forsecuring said blade to rotate,-annular means being provided, belowthreads on said tang sections, to hold said sections in assemblerelationship. I

4. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided with threads and with means forsecuring said blade to rotate,an intermediate portion of each tangsection being provided with additional threads for the reception of alocking-element; and an annular locking-element thereon.

5. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided with means for said blade torotate,-the respective sections of said tang being provided with meanspermitting a downward circulation of a lubricating liquid therethrough.

6. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided With threads and with means forsecuring said blade to rotate,said shank being provided with meanspermitting a downward circulation of a lubricating liquid externallythereof.

7. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlar ement;and a sectional tang element, provi ed with threads and with means forcausing said blade to rotate,said bit being provided with means for adownward circulation of a lubricating liquid.

8. In a drill bit: a blade formed of a material too hard for convenientmachining and provided with a shank which has a terminal enlargement;and a sectional tang element provided with threads and with means forcausing said blade to rotate,-the threads on said tang being engageableby interior threads within a threaded box, for a locking efiect.

9. In a drill bit: a blade formed of a material too hard for convenientmachining and provided withv a shank which has a terminal enlargement;and a sectional tang element provided with threads and with means forcausing said blade to rotate,-the threads on said tang being engageableby interior threads within a threaded box, for a looking efiect; andadditional annular means heing provided to hold the mentioned partsassembled. 4 a

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 19th day of March, 1927.-

GEORGE D. SHIELDS.

